Device and method for over-current protection

ABSTRACT

An over-current protection device for a power generator includes a first pin, configured to receive a signal; a detection and control module, coupled to the first pin, and configured to detect the signal to determine whether the signal conforms to a pre-determined condition or not, and to output a control signal when the signal conforms to the pre-determined condition; and an auto-trim and memory module, coupled to the detection and control module, and configured to receive the control signal from the detection and control module for executing corresponding auto-trim measurements and storing corresponding adjustment data.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional application No.62/693,419, which was filed on 2018 Jul. 2 and is included herein byreference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a device and method for over-currentprotection, and more particularly, to a device and method forover-current protection by load current or load voltage.

2. Description of the Prior Art

A power generator is utilized for supplying power to an electronicdevice. In order to avoid the power generator providing over (excess)current to the electronic device, an over-current protection device isusually implemented in the power generator, which can detect a loadcurrent to inform the power generator to take over-current protectionmeasurements when the load current is too high. This implementationrequires a specific control pin for the power generator in order to setfunctions, e.g. on/off, over-current protection point or power goodoutput (PGO). When the specific control pin of the power generator isremoved, the above functions cannot be set, and therefore it cannot beeffectively determined whether a load current is too high. Improvementsto the prior art are required.

SUMMARY OF THE INVENTION

In order to solve the above mentioned problems, the present inventionprovides a device and method for over-current protection capable ofreceiving signals related to status settings of the over-currentprotection device without implementing extra control pins.

In an aspect, the present invention discloses An over-current protectiondevice for a power generator, comprising: a first pin, configured toreceive a signal; a detection and control module, coupled to the firstpin, and configured to detect the signal to determine whether the signalconforms to a pre-determined condition or not, and to output a controlsignal, when the signal conforms to the pre-determined condition; and anauto-trim and memory module, coupled to the detection and controlmodule, configured to receive the control signal from the detection andcontrol module to execute corresponding auto-trim measurements and tostore corresponding adjustment data.

In another aspect, the present invention discloses an over-currentprotection method for a power generator, comprising: receiving a signal;detecting a voltage level, a voltage waveform, a voltage frequency, avoltage duty cycle, a current size, a current frequency or a currentvariation cycle of the signal to determine whether the signal conformsto a predetermined condition or not; outputting a control signal, whenthe signal conforms to the pre-determined condition; and executingcorresponding auto-trim measurements and storing correspondingadjustment data according to the control signal.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an over-current protection circuitaccording to an embodiment of the present invention.

FIG. 2 to FIG. 4 are circuit diagrams of a detection and control moduleof an over-current protection circuit in FIG. 1 according to anembodiment of the present invention.

FIG. 5 is a schematic diagram of another over-current protection circuitaccording to an embodiment of the present invention.

FIG. 6 and FIG. 7 are circuit diagrams of a detection and control moduleof the over-current protection circuit in FIG. 5 according to anembodiment of the present invention.

FIG. 8 and FIG. 9 are schematic diagrams of an output signal of acomparator according to an embodiment of the present invention.

FIG. 10 is a schematic diagram of an over-current protection circuitaccording to an embodiment of the present invention

FIG. 11 is a schematic diagram of an over-current protection methodaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of an over-current protection circuit 10according to an embodiment of the present invention. The over-currentprotection circuit 10 may be utilized in a power generator PG whichincludes an over-current protection device 100 and a load signalgenerator 12, wherein the power generator PG may be a power supplier, orin a power supplier including the power generator PG and theover-current protection device 100. The load signal generator 12 mayconsist of a load machine (not depicted in the figure) and/or a signalgenerator (not depicted in the figure). The load machine may generate asignal LS of current type, and the signal generator may generate asignal LS of voltage type, such that the signal LS generated by the loadsignal generator 12 may be a voltage signal and/or a current signal. Theover-current protection device 100 may be an over-current protectionchip, which includes a first pin P1, a detection and control module 102,an auto-trim and memory module 104 and a variable current source CS. Thefirst pin P1 is configured to receive the signal LS generated by theload signal generator 12. The detection and control module 102 iscoupled to the first pin P1, for detecting a voltage level, a voltagewaveform, a voltage frequency, a voltage duty cycle, a current size, acurrent frequency or a current variation cycle of the signal LS todetermine whether the signal LS conforms to a predetermined condition ornot, so as to output a control signal cmd1 when the signal LS conformsto the predetermined condition. In addition, the detection and controlmodule 102 may further output a control signal cmd2 to control othercircuits (not depicted in the figure) inside the over-current protectiondevice 100. The auto-trim and memory module 104 is coupled to thedetection and control module 102, for receiving the control signal cmd1from the detection and control module 102, so as to accordingly generateadjustment data d1 and execute corresponding auto-trim measurements. Theauto-trim and memory module 104 includes a memory unit (not depicted inthe figure) for storing the adjustment data d1. The variable currentsource CS is coupled to the first pin P1, the detection and controlmodule 102 and the auto-trim and memory module 104 for adjusting acurrent Ic according to the adjustment data d1.

In an embodiment, the power generator PG includes resistors Rs, Rc. Theload signal generator 12 is configured to generate the signal LS. Asignal LS1 is generated after the signal LS passes the power generatorPG The first pin P1 of the over-current protection device 100 receivesthe signal LS1, and the detection and control module 102 detects thesignal LS1 to generate the control signal cmd1 corresponding to theauto-trim measurements according to the predetermined condition, whichis then transmitted to the auto-trim and memory module 104, wherein thepredetermined condition may be whether the voltage level, the voltagewaveform, the voltage frequency or the voltage duty cycle of the signalLS1 is higher than a default value over a specific period or not. Forexample, the detection and control module 102 may detect whether thevoltage level of the signal LS1 is higher than a voltage VH. When thedetection and control module 102 detects that the voltage level of thesignal LS1 is higher than the voltage VH for a default time, e.g. 10 ms,20 ms or 30 ms, the detection and control module 102 generates thecontrol signal cmd1 corresponding to the auto-trim measurements andtransmits the control signal cmd1 to the auto-trim and memory module104. The auto-trim and memory module 104 generates the adjustment datad1 according to the control signal cmd1 so as to execute thecorresponding auto-trim measurements and store the correspondingadjustment data d1. Therefore, the over-current protection device 100according to an embodiment of the present invention may detect thevoltage level, the voltage waveform, the voltage frequency or thevoltage duty cycle of the signal LS1 or LS through the first pin P1,without implementing extra pins to receive commands of over-currentprotection or status setting data, such that the detection and controlmodule 102 may detect the signal LS1 or LS and the auto-trim and memorymodule 104 may execute corresponding auto-trim measurements and storethe corresponding adjustment data. In another embodiment, the first pinP1 of the over-current protection device 100 may receive the signal LSgenerated by the load signal generator 12 as described in the aboveembodiment, and the detection and control module 102 may generate thecontrol signal cmd1 corresponding to the auto-trim measurementsaccording to the predetermined condition of the signal LS and transmitthe control signal cmd1 to the auto-trim and memory module 104, so as toexecute corresponding auto-trim measurements and store the correspondingadjustment data.

Refer to FIG. 2, which is a circuit diagram of the detection and controlmodule 102 of the over-current protection device 100 according to anembodiment of the present invention. As shown in FIG. 2, the detectionand control module 102 may consist of a comparator 206, resistors R1, R2and a reference voltage Vref. In this embodiment, the detection andcontrol module 102 is coupled to the first pin P1. A division ratio ofthe resistors R1, R2 may be utilized for measuring a high voltage levelof the signal LS1, such that the detection and control module 102 maycompare a voltage of the received signal LS1 with that of the referencevoltage Vref to detect a highest voltage. In other words, the detectionand control module 102 may detect the voltage level of the signal LSfrom the load signal generator 12.

FIG. 3 is a circuit diagram of the detection and control module 102 ofthe over-current protection device 100 according to another embodimentof the present invention. As shown in FIG. 3, the detection and controlmodule 102 consists of comparators 306, 308 and reference voltagesVref_H, Vref_L. In this embodiment, the detection and control module 102is coupled to the first pin P1, such that the detection and controlmodule 102 may respectively compare a voltage of the received signal LS1with the reference voltages Vref_H, Vref_L to detect a highest voltagelevel and a lowest voltage level. Therefore, when the detection andcontrol module 102 detects that the voltage level of the signal LS1 ishigher than Vref_H or lower than the reference voltage Vref_L, thecontrol signal cmd1 corresponding to the auto-trim measurements isgenerated and is transmitted to the auto-trim and memory module 104, soas to execute corresponding auto-trim measurements and store thecorresponding adjustment data.

In another embodiment, the detection and control module 102 may consistof a comparator 406, a frequency counting circuit 408 a and a referencevoltage Vref_M, as shown in FIG. 4. In this embodiment, the detectionand control module 102 is coupled to the first pin P1, such that thedetection and control module 102 may compare a voltage waveform of thereceived signal LS1 with that of the reference voltage Vref_M and thefrequency counting circuit 408 may perform sampling for the voltagewaveform at a frequency F0 to determine a voltage frequency and avoltage duty cycle of the voltage waveform. Therefore, when thedetection and control module 102 detects that the voltage frequency orthe voltage duty cycle of the signal is different, the control signalcmd1 may be generated corresponding to the auto-trim measurements and istransmitted to the auto-trim and memory module 104.

For example, a high voltage level and a low voltage level of the voltagewaveform of the signal LS1 may be respectively decoded as a digitalsignal 1 and a digital signal 0, i.e. the voltage waveform may betransformed into a square waveform by the comparator 406, and the squarewaveform is inputted to the frequency counting circuit 40 for samplingat frequency F0. As such, when the detection and control module 102detects the voltage waveform of the signal LS1 and decodes the digitalsignals, the detection and control module 102 generates the controlsignal cmd1 corresponding to the auto-trim measurements according to thedigital signals, and transmits the control signal cmd1 to the auto-trimand memory module 104. Notably, the detection and control module 102 maydetect a frequency or a voltage duty cycle of the voltage waveform ofthe signal LS1 to generate the control signal cmd1 corresponding to theauto-trim measurements.

FIG. 5 is a schematic diagram of an over-current protection circuit 50according to an embodiment of the present invention. The over-currentprotection circuit 50 includes a load signal generator 12, a powergenerator PG and an over-current protection device 500. The over-currentprotection device 500 includes a first pin P1, a second pin P2, adetection and control module 502, an auto-trim and memory module 504 anda variable current source CS. Compared with the over-current protectiondevice 100 in FIG. 1, the over-current protection device 500 furtherincludes the second pin P2, which is coupled to the detection andcontrol module 102 to receive a signal LS2. The detection and controlmodule 502 respectively receives the signals LS1 and LS2 by the firstpin P1 and the second pin P2 to detect a current signal of the signal LSby a voltage across the first pin P1 and the second pin P2. When thesignal LS conforms to the predetermined condition, the detection andcontrol module 502 outputs the control signal cmd1 to the auto-trim andmemory module 504. As shown in FIG. 5, when the load signal generator 12changes the current of the signal LS, the detection and control module502 may determine the current signal of the signal LS according to avoltage difference, since the voltage difference exists between thefirst pin P1 and the second pin P2. Thus, when the detection and controlmodule 502 detects that a current value of the current signal is higherthan a default value for a specific period, the detection and controlmodule 502 generates the control signal cmd1 corresponding to theauto-trim measurements and transmits the control signal cmd1 to theauto-trim and memory module 504 to execute corresponding auto-trimmeasurements and store the corresponding adjustment data.

Notably, the detection and control module 502 may detect the currentsize, the current frequency or the current variation cycle of the signalLS to generate the control signal cmd1 corresponding to the auto-trimmeasurements. FIG. 6 is a circuit diagram of the detection and controlmodule 502 of the over-current protection device 500 according to anembodiment of the present invention. In FIG. 6, the detection andcontrol module 502 includes a differential comparator 606, a multiplexerMUX, a voltage adder 608 and a counter 610, wherein the multiplexer MUXselects one of reference voltages V1-VN according to the counter 610,e.g. the reference voltage V1, and the voltage adder 608 may output asum voltage of the reference voltage V1 and the signal LS1 to thedifferential comparator 606, so as to compare a voltage differencebetween the first pin P1 and the second pin P2. The counter 610 countsan output signal of the differential comparator 606 based on a clockCLK. In this embodiment, whenever the differential comparator outputsthe high voltage level to the counter 610, i.e. the voltage of thesecond pin P2 is higher than the voltage of the sum of the first pin P1and the selected reference voltage, the multiplexer MUX adjusts itsreference voltage, e.g. the reference voltage V1 is adjusted to thereference voltage V2 and so on, until the differential comparator 606outputs the low voltage level, i.e. the voltage of the second pin P2 islower than the voltage of the sum of the first pin P1 and the selectedreference voltage. Therefore, the detection and control module 502 maydetect the current value of the signal by the voltage across the firstpin P1 and the second pin P2.

FIG. 7 is a circuit diagram of the detection and control module 502 ofthe over-current protection device 500 according to another embodimentof the present invention. The detection and control module 502 mayconsist of a differential comparator 706, a multiplexer MUX, a voltageadder 708 and a frequency counting circuit 710. In this embodiment, thedetection and control module 502 is coupled to the first pin P1 and thesecond pin P2. The detection and control module 502 detects a voltageacross the first pin P1 and the second pin P2 to detect the currentwaveform. The detection and control module 502 selects one of thereference voltages V1-VN of the multiplexer MUX, e.g. the referencevoltage V1, and the voltage adder 708 may output a sum voltage of thereference voltage V1 and the signal LS1, to compare with the signal LS2of the second pin P2. Then, the frequency counting circuit 710 performssampling for the current waveform at the frequency F0 to determine acurrent frequency or a current duty cycle of the current waveform. Thus,when the detection and control module 502 detects signals with differentcurrent frequency or different current duty cycle, the control signalcorresponding to different auto-trim measurements may be generated tothe auto-trim and memory module 504.

The detection and control module according to an embodiment of thepresent invention may generate the control signal cmd1 corresponding tothe auto-trim measurements to the auto-trim and memory module, when thedetection and control module detects the signal of different voltagefrequency or different current duty cycle. Alternatively, the detectionand control module according to an embodiment of the present inventionmay further output the control signal cmd2 to control other circuitsinside the over-current protection circuit 10. In an embodiment, whenthe output signal of the comparator 406 in FIG. 4 and the differentialcomparator 706 in FIG. 7 is the waveform shown in FIG. 8, i.e. when theoutput signal of the comparator 406 or the differential comparator 706is at a HIGH voltage level, the frequency counting circuits 408, 710detect waveform width of its output signal to determine thecorresponding control signal. For example, when the output signal is atthe HIGH voltage level for over a period of time T1, the frequencycounting circuits 408, 710 may output the control signal cmd1 to theauto-trim and memory module. In another example, when the output signalis at the HIGH voltage level for over a period of time T2, the frequencycounting circuits 408, 710 may output the control signal cmd2 to controlother circuits inside the over-current protection circuit 10. Notably,the control signals corresponding to the output signal are not limitedto the above examples and may be modified according to requirements of asystem or a user, so as to correspond to different commands withdifferent waveforms.

In another embodiment, when the output signal of the comparator 406 ordifferential comparator 706 is the waveform shown in FIG. 9, thefrequency counting circuits 408, 710 may detect the duty cycle ofwaveform of its output signal to determine the corresponding controlsignal. For example, when the output signal is a digital series 10101,the frequency counting circuits 408, 710 may output the control signalcmd1 to the auto-trim and memory module. In another example, when theoutput signal is a digital series 10111 (not depicted in the figure),the frequency counting circuits 408, 710 may output the control signalcmd2 to control other circuits inside the over-current protectioncircuit 10. Notably, the control signals corresponding to the outputsignal are not limited to the above examples and may be modifiedaccording to requirements of a system or a user, so as to correspond todifferent commands with different digital series.

Refer to FIG. 10, which is a schematic diagram of an over-currentprotection circuit 10′ according to an embodiment of the presentinvention. The over-current protection circuit 10′ includes a loadsignal generator 12 and an over-current protection device 1000, whereinthe over-current protection device 1000 includes a detection and controlmodule 1002 and an auto-trim and memory module 1004 for being applied tothe power generator PG with a plurality of power supplying modules. Inthis embodiment, the load signal generator 12 may output the signalsLS_A, LS_B and LS_C to corresponding power supplying modules. Thedetection and control module 1002 may receive signals with multiplevoltage waveforms or current waveforms through the first pins P1A, P1B,P1C and the second pins P2A, P2B, P2C corresponding to different powersupplying modules, so as to decode and output the control signal tomultiple power supplying modules for determining the working mode of thepower supplying modules. Notably, the over-current protection device1000 may be simultaneously utilized for controlling the power generatorPG with different amounts of power supplying modules and is not limitedto the above embodiments.

An operation method of the over-current protection device of the presentinvention may be an over-current protection method 1100, as shown inFIG. 11. The over-current protection method 1100 includes the followingsteps:

Step 1102: Start.

Step 1104: Receive the signal.

Step 1106: Detect the signal to determine whether the signal conforms tothe predetermined condition or not.

Step 1108: Output the control signal when the signal conforms to thepre-determined condition.

Step 1110: Execute the corresponding auto-trim measurements according tothe control signal.

Step 1112: Store the corresponding adjustment data according to thecontrol signal.

Step 1114: End.

The operation of the over-current protection method 1100 can be known byreferring to the embodiments of the over-current protection devicedescribed above, and are therefore not repeated herein for brevity.

Notably, those skilled in the art may make modifications to properlydesign the over-current protection device based on different systemrequirements. For example, the circuit diagram of the detection andcontrol module is not limited to the above embodiments. Other circuits,which may be utilized for detecting signals of the voltage waveform,current waveform, frequency, duty cycle of the signal, are all withinthe scope of the present invention. Alternatively, the second pinaccording to an embodiment of the present invention may be independentlyutilized for detecting a voltage signal of the signal and not limitedthereto.

In summary, the present invention provides an over-current protectiondevice and method thereof to obtain a control signal by changing loadcurrent and load voltage without implementing extra control pins toreceive signals related to a setting status of the over-currentprotection device so as to set a working mode of the over-currentprotection device.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An over-current protection device for a powergenerator, comprising: a first pin, configured to receive a signal; adetection and control module, coupled to the first pin, and configuredto detect the signal to determine whether the signal conforms to apre-determined condition or not, and to output a control signal when thesignal conforms to the pre-determined condition; and an auto-trim andmemory module, coupled to the detection and control module, configuredto receive the control signal from the detection and control module,wherein the auto-trim and memory module is configured to execute aplurality of auto-trim measurements and to store adjustment datacorresponding to the plurality of auto-trim measurements; wherein thesignal is generated by a load signal generator, and the first pin is theonly pin between the load signal generator and the detection and controlmodule.
 2. The over-current protection device of claim 1, wherein thedetection and control module is configured to detect a voltage level, avoltage waveform, a voltage frequency, a voltage duty cycle, a currentsize, a current frequency or a current variation cycle of the signal. 3.The over-current protection device of claim 2, wherein the auto-trim andmemory module is configured to store different auto-trim measurementscorresponding to the control signal.
 4. The over-current protectiondevice of claim 1, wherein when the power generator comprises aplurality of power supplying modules, the detection and control moduleoutputs the control signal to the auto-trim and memory module todetermine working modes corresponding to the plurality of powersupplying modules, wherein the working modes are an on setting, an offsetting, or an over-current protection point setting of the plurality ofpower supplying modules.
 5. An over-current protection method for apower generator, comprising: receiving a signal from a first pin;detecting a voltage level, a voltage waveform, a voltage frequency, avoltage duty cycle, a current size, a current frequency or a currentvariation cycle of the signal by a detection and control module todetermine whether the signal conforms to a predetermined condition ornot; outputting a control signal from an auto-trim and memory module,when the signal conforms to the pre-determined condition; and executinga plurality of auto-trim measurements and storing adjustment datacorresponding to the plurality of auto-trim measurements according tothe control signal; wherein the signal is generated by a load signalgenerator, and the first pin is the only pin between the load signalgenerator and the detection and control module.
 6. The over-currentprotection method of claim 5, further comprising: detecting a currentsignal of the signal and outputting the control signal when the signalconforms to the pre-determined condition.
 7. The over-current protectionmethod of claim 6, further comprising: detecting the voltage level, thevoltage waveform, the voltage frequency or the voltage duty cycle of thesignal at a predetermined period to determine whether the signalconforms to the pre-determined condition or not.
 8. The over-currentprotection method of claim 5, wherein the control signal is a workingmode related to the power generator, wherein the working mode is an onsetting, an off setting, or an over-current protection point setting ofthe power generator.